Why is this not something that can easily be done?
Fair question.
I was already here when the current "mods must change" policy was implemented. What I know from that long-ago time are two things based on my observation:
1 — Some people abused the "change it yourself" privilege and became "shapeshifters" who would flame a user and disrupt a thread, then come back the next day under a new name and do more damage. We lost some excellent, long-serving helpers as a result. The mods were playing "Whack-a-Mole" trying to control these idiots.
2 — those problems stoped immediately when the "mods must change" policy took effect.
Again, those were my observations. I don't know the Apple reasons, if different. Nor do I know if that was the only implementation used to stop the bleeding of valuable knowledge,
So it appears that, once again, people who cannot control their urges to be disruptive cost you and me useful privileges.